Thermostats are widely regarded as being useful for controlling the temperature of rooms, ovens, pipes, floors, etc. These devices have been provided for many decades with increasingly useful features, such as larger range of application temperatures, improved accuracy, improved styling, etc.
Easy Heat Limited (EH) manufacture electric heating cables for a variety of applications including snow melting, pipe freeze protection, floor heating, etc. More detail can be viewed at www.easyheat.com. EH also provide a variety of controls for each application, such as thermostats, snow sensors, ground fault sensors, etc.
One of EH's main product lines is floor heating cables that are used to warm floors of homes, especially bathroom floors, but also kitchens, foyers, etc. This product is most popular for use with ceramic/marble type floors due to the inherently “cold” nature of such floors. EH also provide a line of thermostats to enable the user to adjust the floor temperature to their personal comfort level. These thermostats have an external sensor that is embedded in the floor to sense the floor temperature, and is wired back to the thermostat control unit. The thermostat has an adjustable temperature setting that is set by the user. This then facilitates the control of the temperature of the floor by turning the heating cables off when the floor has reached the temperature setting (setpoint) and then turning them on again when the floor temperature has fallen below the setpoint.
Further, some of the thermostats provided by EH have electronic capabilities, such as digital display, clock, etc. so that additional features can be provided. One of the most desirable features is the “setback” program. This feature allows the user to select the time periods (“events”) when they can tolerate a lower floor temperature, such as, say, when they are sleeping, and to select time periods when they prefer a warmer floor temperature, such as, say, when they get up in the morning and use the bathroom. Clearly, this feature provides the user with convenience and allows the user to save considerable energy by warming the floor only when it is expected to be used. These thermostats are typically provided with a “default” program in them to adjust the floor during four separate events, such as follows:                6 am to 8 am: Floor temperature set to 85° F. (“Wake” event)        8 am to 5 pm: Floor temperature set to 60° F. (“Leave” event)        5 pm to 9 pm: Floor temperature set to 85° F. (“Return” event)        9 pm to 8 am: Floor temperature set to 60° F. (“Sleep” event)        
The time and temperature settings are all adjustable, thus allowing the users to “program” their thermostat to suit their lifestyle. Further, the utility of the setback thermostats can be enhanced by offering a “5/2” option or a “7 Day” option. In the 5/2 option, the days of the week (Monday to Friday) are considered to be identical and the weekends (Saturday and Sunday) are also considered to be identical, but not necessarily identical to the weekdays. In the 7 Day mode, each day can be “unique” in that different time/temperature settings can be made for each day. The 7 Day option is important to users who do not have a regular “weekday/weekend” type lifestyle but do have a regular “weekly” lifestyle—i.e. their Mondays are always the same, Tuesdays may be different than Mondays, but all Tuesdays would be the same, etc.
One additional issue of note is that ceramic/marble type floors have a large “thermal mass,” meaning that they heat up slowly and they cool down slowly. As a result, it is necessary to energize the heating cables well in advance of usage, typically at least one hour and this “anticipation” feature is typically built into the setback thermostats. This further eliminates any value in attempting to deenergize the system for a short duration such as, say, 10 minutes, as the floor will cool only slightly in this time and then will take that much longer to get back up to temperature after restarting.
While the standard setback thermostat as described above has provided utility for many years, there are certain problems that it still has not overcome. Mainly, these units are typically esoteric to program and often require the user to refer to a lengthy, complicated owner's manual. Further, with only four events per day, this often does not recognize the diverse lifestyle of modern users. For example, it would not be uncommon on any given day for the bathroom to be used as follows:
Occupied from 5:30 to 6 am
Unoccupied 6 am to 8 am
Occupied 8 am to 9 am
Unoccupied 9 am to 3 pm
Occupied 3 pm to 3:30 pm
Unoccupied 3:30 pm to 6 pm
Occupied 6 pm to 7 pm
Unoccupied 7 pm to 10 pm
Occupied 10 pm to 11 pm
Unoccupied 11 pm to 5:30 am
Clearly, the typical, four-event, setback thermostat will not be able to exactly match this usage. Probably, it would have to be programmed to turn on at 5:30 am and stay on till 9 am, then off till 3 pm then on till 11 pm, then off until 5:30 am. This would increase energy usage from, ideally, 4.5 hours to 11.5 hours—almost tripling energy usage! Of course, this problem could be addressed by increasing the number of events from four to, say, 8—but this will further complicate the “programming” procedure.
The standard setback thermostat also does not easily accommodate changes to usage patterns—whether this is a result of lifestyle changes, such as a new job with different working hours, or even going on vacation—these changes require manual intervention, usually reprogramming of the thermostat with the corresponding frustration that most users experience in attempting to accomplish this change. Again, users typically simply ignore these changes, which results in discomfort and/or energy waste.
Setback thermostats are, generally, highly regarded in the industry as they theoretically allow customers to save energy costs. Governments promote them and often provide incentives for users to purchase them. However, the problem is that, in actual experience, very few of these units are ever used in the “programmable” mode—most users simply put them in “manual” mode and leave them in such a mode, thereby having the thermostat control the floor temperature at the same level at all times, rather than de-energizing the cables during periods when the room is not occupied. The reason for this, it is believed, is that the thermostats are too time-consuming and/or complicated for the average user to “program.”